Class Of Plant Hormones Research Articles

Phytohormone production by the arbuscular mycorrhizal fungus Rhizophagus irregularis

Arbuscular mycorrhizal symbiosis is a mutualistic interaction between most land plants and fungi of the glomeromycotina subphylum. The initiation, development and regulation of this symbiosis involve numerous signalling events between and within the symbiotic partners. Among other signals, phytohormones are known to play important roles at various stages of the interaction. During presymbiotic steps, plant roots exude strigolactones which stimulate fungal spore germination and hyphal branching, and promote the initiation of symbiosis. At later stages, different plant hormone classes can act as positive or negative regulators of the interaction. Although the fungus is known to reciprocally emit regulatory signals, its potential contribution to the phytohormonal pool has received little attention, and has so far only been addressed by indirect assays. In this study, using mass spectrometry, we analyzed phytohormones released into the medium by germinated spores of the arbuscular mycorrhizal fungus Rhizophagus irregularis. We detected the presence of a cytokinin (isopentenyl adenosine) and an auxin (indole-acetic acid). In addition, we identified a gibberellin (gibberellin A4) in spore extracts. We also used gas chromatography to show that R. irregularis produces ethylene from methionine and the α-keto γ-methylthio butyric acid pathway. These results highlight the possibility for AM fungi to use phytohormones to interact with their host plants, or to regulate their own development.

Identification, localization and expression analysis of beta-carotene isomerase gene family in sugarcane

<p indent=0mm>Strigolactones (SLs), a class of plant hormones, exists widely in plants and involves in the regulation of plant tillering and environmental adaptation. β-carotene isomerase (D27) is a key enzyme for SLs synthesis, but there are few reports about the identification and analysis of <italic>D27</italic> gene family in sugarcane. In this study, five members of <italic>D27</italic> gene family from one of the original parent of modern sugarcane cultivars, <italic>Saccharum spontaneum</italic>, were analyzed. Phylogenetic tree analysis showed that these D27s from <italic>S</italic>.<italic> spontaneum</italic> was clustered into 3 different branches and were highly homologous to sorghum D27s. Conserved domain prediction revealed that D27s contained a typical domain of β-carotene isomerase, Pfam: DUF4033. The results of cis-element analysis showed that<italic> D27s</italic> mainly involved in the regulation of hormone response, plant growth and development, and stress response. Based on the transcriptomic data of the modern cultivated varieties, the expression analysis of the homologous transcripts of <italic>Saccharum spontaneum D27s</italic> showed that <italic>Sspon</italic>.<italic>06G0012830-1A</italic> was regulated at tillering stage and under <italic>Sporisorium scitamineum </italic>infection. Besides, the cDNA sequence of <italic>Sspon</italic>.<italic>06G0012830-1A</italic> was cloned from sugarcane cultivar ROC22 and named as <italic>ScD27</italic>.<italic>1 </italic>(GenBank accession number: MT499895). Bioinformatics analysis indicated that <italic>ScD27</italic>.<italic>1</italic> encoded an unstable protein of 266 amino acids with an isoelectric point of 8.91 and a molecular weight of 30.00 kD, and might be located in the chloroplast, containing chloroplast transit peptides, 4 ubiquitination sites and 18 phosphorylation sites. Its secondary structure mainly included alpha helix and random coils. qRT-PCR analysis demonstrated that <italic>ScD27</italic>.<italic>1</italic> was significantly induced by ABA and H₂O₂ and did not respond to MeJA and SA. Subcellular localization revealed that ScD27.1 might be located in cell membrane and chloroplast and involved in the vesicle sorting or transported by sorting vesicle in plant cells. The results suggested that <italic>ScD27</italic>.<italic>1</italic> may involve in the tillering induced by <italic>S</italic>.<italic> scitamineum </italic>and signaling pathway of ABA and H₂O₂. The present study provides a basic understanding of intracellular transport and tillering in sugarcane and the involvement of <italic>ScD27</italic>.<italic>1 </italic>during sugarcane-<italic>S</italic>.<italic> scitamineum</italic> interaction.

Isoflavones and inflammatory bowel disease.

Isoflavones constitute a class of plant hormones including genistein, daidzein, glycitein, formononetin, biochanin A, and irilone, and the major source of human intake is soybeans. Inflammatory bowel disease (IBD) is a chronic recurrent inflammatory disease including ulcerative colitis, Crohn's disease, and indeterminate colitis, which seriously affects the quality of life of patients and has become a global health problem. Although the pathogenesis of IBD is not very clear, many factors are thought to be related to the occurrence and development of IBD such as genes, immunity, and intestinal flora. How to control IBD effectively for a long time is still a problem for gastroenterologists. Diet has an important effect on IBD. Patients with IBD should pay more attention to diet. To date, many studies have reported that isoflavones have both good and bad effects on IBD. Isoflavones have many activities such as regulating the inflammatory signal pathways and affecting intestinal barrier functions and gut flora. They can also act through estrogen receptors, as they have a similar structure to estrogen. Isoflavones are easy to get from diet for human. Whether they are valuable to be applied to the treatment of IBD is worth studying. This review summarizes the relationship between isoflavones and IBD.

An improved extraction method enables the comprehensive analysis of lipids, proteins, metabolites and phytohormones from a single sample of leaf tissue under water-deficit stress.

Phytohormones play essential roles in the regulation of growth and development in plants. Plant hormone profiling is therefore essential to understand developmental processes and the adaptation of plants to biotic and/or abiotic stresses. Interestingly, commonly used hormone extraction and profiling methods do not adequately resolve other molecular entities, such as polar metabolites, lipids, starch and proteins, which would be required to comprehensively describe the continuing biological processes at a systematic level. In this article we introduce an updated version of a previously published liquid:liquid metabolite extraction protocol, which not only allows for the profiling of primary and secondary metabolites, lipids, starch and proteins, but also enables the quantitative analysis of the major plant hormone classes, including abscisic acid, auxins, cytokinins, jasmonates and salicylates, from a single sample aliquot. The optimization of the method, which uses the introduction of acidified water, enabling the complete purification of major plant hormones into the organic (methyl-tert-butyl-ether) phase, eliminated the need for solid-phase extraction for sample clean-up, and therefore reduces both sampling time and cost. As a proof-of-concept analysis, Arabidopsis thaliana plants were subjected to water-deficit stress, which were then profiled for hormonal, metabolic, lipidomic and proteomic changes. Surprisingly, we determined not only previously described molecular changes but also significant changes regarding the breakdown of specific galactolipids, followed by the substantial accumulation of unsaturated fatty-acid derivatives and diverse jasmonates in the course of adaptation to water-deficit stress.

Do Phosphate and Cytokinin Interact to Regulate Strigolactone Biosynthesis or Act Independently?

Strigolactones (SLs) are essential host recognition signals for both root-parasitic plants and arbuscular mycorrhizal (AM) fungi in the rhizosphere, and in planta SLs or their metabolites function as a novel class of plant hormones that regulate various aspects of plant growth through crosstalk with other hormones. Although nutrient availability is one of the important factors influencing SL production and exudation, and phosphate (Pi) deficiency significantly promotes SL production and exudation in host plants of AM fungi, how nutrient availability modulates SL production and exudation remains elusive. Cytokinin (CK), a canonical plant hormone, has extensively been studied as a shoot branching promoter and its biosynthesis is also influenced by mineral nutrients, especially nitrate, indicating that CK might be another key factor that affect SL production and exudation. In the present study, we show that CKs (t-zeatin, benzyladenine, kinetin, and CPPU) applied to hydroponic culture media significantly suppressed the SL levels in both the root exudates and the root tissues of rice plants grown under Pi deficiency. In a split-root system, CK suppressed SL production locally, while Pi affected SL production systemically, suggesting that Pi and CK act on SL production independently in rice plants.

Strigolactone Analogs Are Promising Antiviral Agents for the Treatment of Human Cytomegalovirus Infection.

The human cytomegalovirus (HCMV) is a widespread pathogen and is associated with severe diseases in immunocompromised individuals. Moreover, HCMV infection is the most frequent cause of congenital malformation in developed countries. Although nucleoside analogs have been successfully employed against HCMV, their use is hampered by the occurrence of serious side effects. There is thus an urgent clinical need for less toxic, but highly effective, antiviral drugs. Strigolactones (SLs) are a novel class of plant hormones with a multifaceted activity. While their role in plant-related fields has been extensively explored, their effects on human cells and their potential applications in medicine are far from being fully exploited. In particular, their antiviral activity has never been investigated. In the present study, a panel of SL analogs has been assessed for antiviral activity against HCMV. We demonstrate that TH-EGO and EDOT-EGO significantly inhibit HCMV replication in vitro, impairing late protein expression. Moreover, we show that the SL-dependent induction of apoptosis in HCMV-infected cells is a contributing mechanism to SL antiviral properties. Overall, our results indicate that SLs may be a promising alternative to nucleoside analogs for the treatment of HCMV infections.

Evidences for Preferential Localization of Cytokinin Receptors of Potato in the Endoplasmic Reticulum

Cytokinins, classical plant hormones, are recognized by the cell through receptors—hybrid sensor histidine kinases, multidomain transmembrane proteins. The character of the hormonal effect on the cell and the mode of the hormonal signal transduction to the primary targets depends on the subcellular localization of the receptors. Recently, we cloned and investigated a family of cytokinin receptors from a new model plant, potato Solanum tuberosum L. Two typical representatives of this family, StHK2a and StHK4b, were selected to study their subcellular localization. In the current study, total membranes isolated from tobacco leaves, in which the selected recombinant potato receptors fused to GFP-reporter were transiently expressed, were fractionated by aqueous two-phase partitioning. Two membrane fractions were obtained, one tentatively enriched with endoplasmic reticulum (ER) membranes and the other, with the plasma membrane (PM). The content of StHK2a and StHK4b in each fraction was determined by the radioligand method. Both receptors were detected in the two fractions, with a slight predominance of StHK4b in the ER-enriched fraction. Given that the content of ER membranes in the cell is markedly higher than the content of the PM, the bulk of the receptors should be attributed to the ER. Specific cytokinin-binding sites were detected in the analogous membrane fractions isolated from non-transformed potato roots. Although the specific content of the cytokinin-binding sites was 1.8-fold higher in the PM, here also, the main part of these sites, i.e., cellular receptors, still resided in the ER. In order to find out whether the receptors in the ER are functional, a recently proposed pH criterion was applied. According to this criterion, potato cytokinin receptors, like their orthologs from other species, seem to be tuned for functioning in the ER but not in the PM. The results of molecular modeling of the dimerization interface of the receptors at different pH values also evidenced in favor of the ER. Thus, the main site of subcellular localization of the functionally active potato cytokinin receptors is the ER, although a certain amount of the receptors resides within the PM, too. The question of the functional role of PM-located receptors remains open.

Science and application of strigolactones.

SummaryStrigolactones (SLs) represent a class of plant hormones that regulate developmental processes and play a role in the response of plants to various biotic and abiotic stresses. Both in planta hormonal roles and ex planta signalling effects of SLs are potentially interesting agricultural targets. In this review, we explore various aspects of SL function and highlight distinct areas of agriculture that may benefit from the use of synthetic SL analogues, and we identify possible bottlenecks. Our objective is to identify where the contributions of science and stakeholders are still needed to achieve harnessing the benefits of SLs for a sustainable agriculture of the near future.

IPyA glucosylation mediates light and temperature signaling to regulate auxin-dependent hypocotyl elongation in Arabidopsis

Auxin is a class of plant hormone that plays a crucial role in the life cycle of plants, particularly in the growth response of plants to ever-changing environments. Since the auxin responses are concentration-dependent and higher auxin concentrations might often be inhibitory, the optimal endogenous auxin level must be closely controlled. However, the underlying mechanism governing auxin homeostasis remains largely unknown. In this study, a UDP-glycosyltransferase (UGT76F1) was identified from Arabidopsis thaliana, which participates in the regulation of auxin homeostasis by glucosylation of indole-3-pyruvic acid (IPyA), a major precursor of the auxin indole-3-acetic acid (IAA) biosynthesis, in the formation of IPyA glucose conjugates (IPyA-Glc). In addition, UGT76F1 was found to mediate hypocotyl growth by modulating active auxin levels in a light- and temperature-dependent manner. Moreover, the transcription of UGT76F1 was demonstrated to be directly and negatively regulated by PIF4, which is a key integrator of both light and temperature signaling pathways. This study sheds a light on the trade-off between IAA biosynthesis and IPyA-Glc formation in controlling auxin levels and reveals a regulatory mechanism for plant growth adaptation to environmental changes through glucosylation of IPyA.

Strigolactones Decrease Leaf Angle in Response to Nutrient Deficiencies in Rice.

Strigolactones (SLs) are a class of plant hormones that are synthesized from β-carotene through sequential reactions catalyzed by DWARF (D) 27, D17, D10, and OsMORE AXILLARY GROWTH (MAX) 1 in rice (Oryza sativa L.). In rice, endogenous SL levels increase in response to deficiency of nitrogen, phosphate, or sulfate (−N, −P, or −S). Rice SL mutants show increased lamina joint (LJ) angle as well as dwarfism, delayed leaf senescence, and enhanced shoot branching. The LJ angle is an important trait that determines plant architecture. To evaluate the effect of endogenous SLs on LJ angle in rice, we measured LJ angle and analyzed the expression of SL-biosynthesis genes under macronutrient deficiencies. In the “Shiokari” background, LJ angle was significantly larger in SL mutants than in the wild-type (WT). In WT and SL-biosynthesis mutants, direct treatment with the SL synthetic analog GR24 decreased the LJ angle. In WT, deficiency of N, P, or S, but not of K, Ca, Mg, or Fe decreased LJ angle. In SL mutants, deficiency of N, P, or S had no such effect. We analyzed the time course of SL-related gene expression in the LJ of WT deficient in N, P, or S, and found that expression of SL-biosynthesis genes increased 2 or 3 days after the onset of deficiency. Expression levels of both the SL-biosynthesis and signaling genes was particularly strongly increased under −P. Rice cultivars “Nipponbare”, “Norin 8”, and “Kasalath” had larger LJ angle than “Shiokari”, interestingly with no significant differences between WT and SL mutants. In “Nipponbare”, endogenous SL levels increased and the LJ angle was decreased under −N and −P. These results indicate that SL levels increased in response to nutrient deficiencies, and that elevated endogenous SLs might negatively regulate leaf angle in rice.

Characterization of the OFP Gene Family and its Putative Involvement of Tuberous Root Shape in Radish.

The shape of the tuberous root, a very important quality trait, varies dramatically among radish cultivars. Ovate family proteins (OFPs) are plant-specific proteins that regulate multiple aspects of plant growth and development. To investigate the possible role of OFPs in radish tuberous root formation, 35 putative RsOFPs were identified from radish, and their expression patterns were detected during tuberous root development in six different radish cultivars. Phylogenetically, RsOFP2.3 clustered together with AtOFP1 and other members of this family that are known to regulate organ shape. Moreover, RsOFP2.3 expression was negatively correlated with tuberous root elongation after the cortex splitting stage, which made this gene the top candidate for the involvement of tuberous root shape. To further characterize the function of RsOFP2.3, it was ectopically expressed in Arabidopsis. RsOFP2.3 overexpression in Arabidopsis led to multiple phenotypical changes, especially the decreased length and increased width of the hypocotyl. Furthermore, RsOFP2.3 expression was induced by all the five classic plant hormones except ethylene, and it was most sensitive to exogenous gibberellic acid treatment. We also found that RsOFP2.3 was localized in the cytoplasm. Taken together, our results suggested the possible involvement for RsOFP2.3 in suppressing radish tuberous root elongation and that it encodes a functional protein which mainly inhibits the elongation of Arabidopsis aerial organs.

Genes involved in strigolactone biosyntheses and their expression analyses in columnar apple and standard apple

Columnar apple is a valuable resource for genetic improvement of cultivated apples due to its special tree architecture. Strigolactones (SLs) are a novel class of plant hormones controlling shoot branching. The content of SLs is higher in columnar apple than in standard apples. In this study, the members of major gene families involved in SLs biosynthesis and signaling were identified from apple genomic sequences and their expression profiles were characterized in columnar and standard apples using reverse transcription quantitative polymerase chain reactions. In comparison with standard apple, the higher expressions of MORE AXILLARY GROWTH genes MdMAX3-1 and MdMAX4-4 were detected in both buds and shoots of columnar apple but the expression of DWARF gene MdD53-4 showed a lower expression in columnar apple. Overexpression of Columnar gene MdCo31 in tobacco increased SLs content and weakened the inhibition of SLs signal transduction by increasing expression of MAX3 and down-regulating the transcription of D53. Thus MdCo31 could be a strong candidate gene for the control of columnar habit.

The Many Models of Strigolactone Signaling.

Strigolactones (SLs) are a class of plant hormones involved in several biological processes that are of great agricultural concern. While initiating plant-fungal symbiosis, SLs also trigger germination of parasitic plants that pose a major threat to farming. In vascular plants, SLs control shoot branching, which is linked to crop yield. SL research has been a fascinating field that has produced a variety of different signaling models, reflecting a complex picture of hormone perception. Here, we review recent developments in the SL field and the crystal structures that gave rise to various models of receptor activation. We also highlight the increasing number of discovered SL molecules, reflecting the existence of cross-kingdom SL communication.

Characterization of indole-3-acetic acid in cambial zone tissue by ultra-performance liquid chromatography-tandem mass spectrometry

The developmental plasticity of plants according to changes in their growth conditions is mediated by signaling molecules called hormones. The major classes of plant hormones are auxin, gibberellins, abscisic acid, and ethylene. Among these, the most important is indole-3-acetic acid (IAA). Quantification of IAA in an extract of approximately 10 mg obtained from the cambial zone of Eucalyptus leaves was performed by ultra-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC/ESI-MS/MS). The leaves were extracted using acetone, and the extract was analyzed using a reverse-phase column (Acquity UPLC BEH C18, 2.1 mm × 100 mm, 1.7 µm) at a flow rate of 0.2 mL/min with gradient elution of an aqueous mobile phase (containing 0.1% formic acid) with methanol. This gradient elution provided an excellent performance in terms of specificity/selectivity, linearity, precision, and ruggedness/stability. In addition, the run time was short (6 min), with excellent linearity (R2 &gt; 0.99) in the range of 10–70 ng/mL. The structure of IAA was elucidated using UPLC/ESIMS/MS, operating and quantifying in multiple reaction monitoring (MRM) mode.

OsIAGT1 Is a Glucosyltransferase Gene Involved in the Glucose Conjugation of Auxins in Rice

BackgroundIn cereal crop rice, auxin is known as an important class of plant hormone that regulates a plethora of plant growth and development. Glycosylation of auxin is known to be one of the important mechanisms mediating auxin homeostasis. However, the relevant auxin glucosyltransferase (GT) in rice still remains largely unknown.ResultsIn this study, using known auxin glucosyltransferases from other species as queries, twelve putative auxin UDP-glycosyltransferase (UGT) genes were cloned from rice and the one showing highest sequence similarity, named as OsIAGT1, was expressed as recombinant protein. In vitro enzymatic analysis showed that recombinant OsIAGT1 was capable of catalyzing glucosylation of IAA, IBA and other auxin analogs, and that OsIAGT1 is quite tolerant to a broad range of reaction conditions with peak activity at 30 °С and pH 8.0. OsIAGT1 showed favorite activity towards native auxins over artificially synthesized ones. Further study indicated that expression of OsIAGT1 can be upregulated by auxin in rice, and with OsIAGT1 overexpressing lines we confirmed that OsIAGT1 is indeed able to glucosylate IAA in vivo. Consistently, ectopic expression of OsIAGT1 leads to declined endogenous IAA content, as well as upregulated auxin synthesis genes and reduced expression of auxin-responsive genes, which likely leads to the reduced plant stature and root length in OsIAGT1 overexpression lines.ConclusionOur result indicated that OsIAGT1 plays an important role in mediating auxin homeostasis by catalyzing auxin glucosylation, and by which OsIAGT1 regulates growth and development in rice.

Effect of D-ring C-3’ methylation of strigolactone analogs on their transcription regulating activity in rice

ABSTRACTStrigolactones (SLs) are a well-known class of plant hormones, which are involved in a number of developmental and adaptation processes and mediate different interspecific interactions. In spite of the growing knowledge on SL biosynthesis and signal transduction, effects of structural modifications on the activity and efficiency of SLs and their analogs remain largely elusive. SLs are characterized by the presence of a lactone ring (D-ring) that is connected by an enol ether bridge to a second moiety. In this study, we investigated the effect of additional D-ring methylation of SL analogs on their transcription regulating activity. For this purpose, we compared the SL analogs MP13 and AR8, which differ only by the presence of a methyl group at the C-3ʹ atom in the latter. Transcription regulating activity was determined by quantitative real-time PCR measurement of transcript levels of SL-dependent, feed-back regulated genes in treated wild type and ccd7 mutant rice seedlings. Results obtained indicate that C-3ʹ methylation reduces the transcription regulating activity, as shown by the more pronounced suppression of the SL biosynthesis genes DWARF27 (D27) and CAROTENOID CLEAVAGE DIOXYGENASES (CCD7 and CCD8) and higher induction of the SL signaling repressor gene DWARF53 (D53) in MP13 treated seedlings. These results are consistent with a recent study on the biological activities of MP13 and AR8.

The Roles of Plant Hormones and Their Interactions with Regulatory Genes in Determining Meristem Activity.

Plants, unlike animals, have developed a unique system in which they continue to form organs throughout their entire life cycle, even after embryonic development. This is possible because plants possess a small group of pluripotent stem cells in their meristems. The shoot apical meristem (SAM) plays a key role in forming all of the aerial structures of plants, including floral meristems (FMs). The FMs subsequently give rise to the floral organs containing reproductive structures. Studies in the past few decades have revealed the importance of transcription factors and secreted peptides in meristem activity using the model plant Arabidopsis thaliana. Recent advances in genomic, transcriptomic, imaging, and modeling technologies have allowed us to explore the interplay between transcription factors, secreted peptides, and plant hormones. Two different classes of plant hormones, cytokinins and auxins, and their interaction are particularly important for controlling SAM and FM development. This review focuses on the current issues surrounding the crosstalk between the hormonal and genetic regulatory network during meristem self-renewal and organogenesis.

Strigolactones: Plant Hormones with Promising Features.

Almost 80 years after the discovery of the first plant hormone, auxin, a few years ago a new class of plant hormones, the strigolactones, was discovered. These molecules have unprecedented biological activity in a number of highly important biological processes in plants but also outside the plant in the rhizosphere, the layer of soil surrounding the roots of plants and teeming with life. The exploitation of this amazing biological activity is not without challenges: the synthesis of strigolactones is complicated and designing the desired activity a difficult task. This minireview describes the current state of knowledge about the strigolactones and how synthetic analogs can be developed that can potentially contribute to the development of a sustainable agriculture.

The strigolactone analog GR-24 inhibits angiogenesis in vivo and in vitro by a mechanism involving cytoskeletal reorganization and VEGFR2 signalling

Phytohormones have shown great potential as natural anticancer compounds, being interesting in cancer prevention and therapy. Strigolactones are a class of plant hormones involved in the inhibition of root branching and sprouting. The antiproliferative capacity of the synthetic strigolactone analog GR-24 has been described against breast cancer cell lines in vitro. In this study, we show for the first time that GR-24 is a potent antiangiogenic compound in vivo and in vitro. In the in vivo tests, GR-24 shows a great inhibitory effect on vasculature formation in the chicken chorioallantoic membrane and in two different zebrafish models. Our in vitro results show that GR-24 inhibits the growth of endothelial cells and different cancer cell lines with a micromolar range of half inhibitory concentration (IC50) values. In addition, GR-24 inhibits key steps of the angiogenic process in vitro, such as tubulogenesis, invasion, extracellular matrix remodeling capacity, migration and adhesion of endothelial cells at non-cytotoxic concentrations. Our data point to an effect of GR-24 on cytoskeleton organization in endothelial cells, in addition to a decrease in focal adhesion kinase (FAK) presence in these cells. All these data, together with the observed increase in surface expression of vascular endothelial-cadherin (VE-cadherin) and platelet and endothelial cell adhesion molecule 1 (PECAM-1), suggest that GR-24 prevents angiogenesis by maintaining the quiescent phenotype in endothelial cells. The proposed mechanism of action underlying the antiangiogenic activity of GR-24 involves the inhibition of VEGFR2 phosphorylation, and the downstream reduction in activation of FAK, a key regulator protein implicated in angiogenesis. Our results suggest that GR-24 may be a promising new compound for antiangiogenic therapy of cancer and other angiogenesis-dependent diseases.

Expression of wheat gibberellins 2-oxidase gene induced dwarf or semi-dwarf phenotype in rice

Gibberellins (GAs) are a class of plant hormones that play important roles in diverse aspects during plant growth and development. A series of GA synthesis and metabolism genes have been reported or proved to have essential functions in different plant species, while a small number of GA 2-oxidase genes have been cloned or reported in wheat. Previous studies have provided some important findings on the process of GA biosynthesis and the enzymes involved in its related pathways. These may facilitate understanding of the complicated process underlying GA synthesis and metabolism in wheat. In this study, GA 2-oxidase genes TaGA2ox1-1, TaGA2ox1-2, TaGA2ox1-3, TaGA2ox1-4, TaGA2ox1-5, and TaGA2ox1-6 were identified and further overexpressed in rice plants to investigate their functions in GA biosynthesis and signaling pathway. Results showed overexpression of GA 2-oxidase genes in rice disrupted the GA metabolic pathways and induced catalytic responses and regulated other GA biosynthesis and signaling pathway genes, which further leading to GA signaling disorders and diversity in phenotypic changes in rice plants.